1. Field of the Invention
The present invention relates to a developed-color measurement apparatus and method for performing quantitative or qualitative measurement about an analyte in a sample solution.
2. Description of the Related Art
Many devices that easily and quickly perform a test about an analyte have been developed in recent years. In the devices, a sample solution that may contain the analyte is supplied to a test strip, and test about the analyte is performed by immunochromatography to test in-vitro diagnostic reagents, toxic substances and the like (please refer, for example, to International Patent Publication No. 2007/007849 (Patent Document 1)). For example, a sample solution is obtained by mixing a sample in which an analyte (for example, an antigen) may be present to a labeled second antibody that specifically binds to the analyte, and the sample solution is developed on an insoluble carrier made of porous material, and on which a first antibody that specifically binds to the analyte is immobilized in a specific area (test line). Then, an antigen-antibody reaction between the analyte and the first antibody and an antigen-antibody reaction between the analyte and the second antibody occur on the test line, and the test line becomes a color developed state as the test line is colored or a change in color occurs on the test line. Quantitative measurement as to whether the analyte is present in the sample solution or qualitative measurement (negative/positive) is performed by observing the color developed state of this test line.
Further, a method has been proposed to improve the reliability of measurement by developing a washing liquid on a test line and the vicinity of the test line (background), thereby removing labels in the background. Accordingly, a noise component is reduced, and an S/N ratio is improved (please refer, for example, to Japanese Unexamined Patent Publication No. 2009-216695 (Patent Document 2)).